I assume you want to continue using the dish for astra 1 so don't want to move it.
So you need to add a second LNB on a side arm bracket. Looking from the front of the dish, the new LNB will a bit to the left of, and slightly higher than the original LNB.
Do not move the dish, or else you will upset your Astra 1 reception. Adjust the position of the second LNB (by adjusting the mounting bracket) for optimum signal strength and quality.
While you are at it, put a third LNB on the other side of the original for Hotbird from 13 degrees E, this will be to the right and slightly lower than the original LNB.